The overall objective of this project is to determine the physiological significances of the general occurrence of cellular folate in the form of folylpolyglutamates. We are purifying and studying the properties of the enzymes of Neurospora crassa and calves' liver with the intention of designing inhibitors that would permit us to determine the biological effect of the failure to carry out this process. Bibliographic references: Ritari, S.J., Sakami, W., Black, C.W. and Rzepka, J. (1975) The Determination of Folylpolyglutamate Synthetase. Anal. Biochem. 63, 118-129.